Table 3.

Model parameters and results for linear mixed effects models with change in muscle length as dependent factor

	Shift * T/M ratio * Limb * Act					T/M ratio * Limb * Act
Model	DF	Sum sq.	Mean sq.	F-value	P-value	Sum sq.	Mean sq.	F-value	P-value
Shift (1)	1	0.02	0.02	17.4	0.15
T/M ratio (2)	1	0.94	0.094	83.1	0.07	0.097	0.097	83.08	0.07
Limb (3)	2	13.07	6.53	5768.2	1.7e−4	6.8	3.3	2808.9	3.6e−4
Act (4)	4	83.87	20.96	18502.8	1.75e−8	41.9	10.5	8964.4	7.4e−8
1×2	1	0.017	0.167	14.70	0.01
1×3	2	0.016	0.008	7.03	0.01
2×3	2	5.95	2.97	2625.2	3.08e-4	3.04	1.5	1300	7.7e-4
1×4	4	0.018	0.005	4.07	0.1
2×4	4	39.83	9.96	8787.3	7.8e−8	19.98	4.99	4265.6	3.3e−7
3×4	8	14.49	1.81	1598.6	1.6e−10	7.5	0.94	804.5	2.6e−9
1×2×3	2	0.005	0.002	2.27	0.2
1×2×4	4	0.013	0.003	2.95	0.16
1×3×4	8	0.022	0.003	2.37	0.16
2×3×4	8	5.78	0.722	637.4	6.4e−9	3.02	0.38	322.1	9.5e−8
1×2×3×4	8	0.008	0.001	0.89	0.3

Activation-dependent shift in L0 (Shift) did not have significant main or interaction effect. Activation level, MTU compliance (TFR), and passive region of the F–L curve all interact to influence operating muscle length. Bolded values highlight models with parameters that significantly influenced muscle length.